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New Scientist Live

Lake life survives in total isolation for 3000 years

By Andy Coghlan

IT’S seven times as salty as the sea, 13 degrees below freezing and sees no light – yet it teems with life. Welcome to Lake Vida in East Antarctica, a liquid haven that has been buried for 2800 years under 20 metres of ice.

The discovery of strange bacteria in a completely sealed, icebound lake strengthens the possibility that extraterrestrial life might exist on icy worlds elsewhere in the solar system.

“Lake Vida is a model of what happens when you try to freeze a lake solid,” says Peter Doran of the University of Illinois, Chicago. “This is the same fate that any lakes on Mars would have gone through as the planet turned colder from a watery past.”

Doran is co-leader of a team working in the McMurdo Dry Valleys of Antarctica, where Vida is situated. “Any Martian water bodies that did form would have gone through this Vida stage before freezing solid, entombing the evidence of the past ecosystem,” he says.

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Any Martian lakes that did form would have gone through this sealed stage before freezing solid

The Vida bacteria, brought to the surface in cores drilled into the ice, belong to previously unknown species. They probably survive by metabolising the abundant quantities of hydrogen and oxides of nitrogen that Vida’s salty, oxygen-free water contains (PNAS, DOI&colon; 10.1073/pnas.1208607190).

Co-leader Alison Murray of the Desert Research Institute in Reno, Nevada, is now investigating this further by growing some of the extracted cells in the lab. “We can use these cultivated organisms to better understand the physical or chemical extremes they can tolerate that might be relevant to other icy worlds such as Europa,” she says.

The team was surprised to find so much hydrogen, nitrous oxide and carbon. Over the centuries, bacteria denied sunlight may have evolved to be reliant on these substances for energy. “The unusual conditions found in the lake have likely played a significant role in shaping the diversity and capabilities of the life we found,” she says.